April 20, 2004
Mild Iron Deficiency Lowers Cognitive Function In Women

Iron deficiency that is so mild that it doesn't cause anemia still reduces cognitive function in women.

Young women who took iron supplementation for 16 weeks significantly improved their attention, short-term and long-term memory, and their performance on cognitive tasks, even though many were not considered to be anemic when the study began, according to researchers at Pennsylvania State University.

The study, the first to systematically examine the impact of iron supplementation on cognitive functioning in women aged 18 to 35 (average age 21), was presented at Experimental Biology 2004, in the American Society of Nutritional Sciences' scientific program. Dr. Laura Murray-Kolb, a postdoctoral fellow in the lab of Dr. John Beard, says the study shows that even modest levels of iron deficiency have a negative impact on cognitive functioning in young women. She says the study also is the first to demonstrate how iron supplementation can reverse this impact in this age group.

Baseline cognition testing, looking at memory, stimulus encoding, retrieval, and other measures of cognition, was performed on 149 women who classified as either iron sufficient, iron deficient but not anemic, or anemic. All of the women underwent a health history, and the research design controlled or took into account any differences in smoking, social status, grade point average, and other measures. The women were then given either 60 mg. iron supplementation (elemental iron) or placebo treatment for four months. At the end of that period, the 113 women remaining in the study took the same task again.

On the baseline test, women who were iron deficient but not anemic completed the tasks in the same amount of time as iron sufficient women of the same age, but they performed significantly worse. Women who were anemia also performed significantly worse, but in addition they took longer. The more anemic a woman was, the longer it took her to complete the tasks. However, supplementation and the subsequent increase in iron stores markedly improved cognition scores (memory, attention, and learning tasks) and time to complete the task.

This finding has great implications, says Dr. Murray-Kolb, because the prevalence of iron deficiency remains at 9 percent to 11 percent for women of reproductive age and 25 percent for pregnant women. In non-industrialized countries, the prevalence of anemia is over 40 percent in non-pregnant women and over 50 percent for pregnant women and for children aged five to 14. According to current prevalence estimates, iron deficiency affects the lives of more than two billion people worldwide.

The findings also are important, say the researchers, because they illustrate the significance of lower amounts of iron deficiency on cognitive functioning, including memory, attention, learning tasks, and time to complete studies.

Some of the known consequences of iron deficiency are reduced physical endurance, an impaired immune response, temperature regulation difficulties, changes in energy metabolism, and in children, a decrease in cognitive performance as well as negative affects on behavior. While iron deficiency was once presumed to exert most of its deleterious effects only if it had reached the level of anemia, it has more recently become recognized that many organs show negative changes in functioning before there is any drop in iron hemoglobin concentration.

Authors of the study are Dr. Murray-Kolb, Dr. Beard, both of the Nutritional Sciences Department at Penn State, and Dr. Keith Whitfield, of Penn State's Biobehavioral Health Department.

Two billion people would operate at a higher level of cognitive function if they received adequate amounts of iron. That represents a huge amount of wasted potential and that is from just one micronutrient deficiency. There may well be other widespread micronutrient deficiencies (choline, omega 3 fatty acids, zinc, and still others) that are reducing cognitive function. But even worse, some of these deficiencies are surely holding back brain development before and after birth and preventing full genetic potential from ever being realized. For people who grow up eating a nutritionally deficient diet supplementation in adulthood will be beneficial. But if a person goes through a stage of development with deficiencies persisting throughout that stage then supplementation that comes later in life will be too late to allow full brain development..

Unfortunately the taboos around IQ help to prevent a full airing of the implications of this sort of research. That is a shame. We need to talk about how to raise IQs and improve mental function by improving nutrition and in other ways as well. For instance, British researchers found that improved nutrition makes prisoners behave much better. Would it also lower crime rates if released prisoners were required to take supplements? Also, a recent report provides preliminary evidence that zinc will lower the severity of attention deficit hyperactivity disorder (ADHD) in children. It may be the case that millions of children would be learning more and disrupting classes less if they were getting more zinc in their diets.

In order to improve average level of mental functioning I am an advocate of both more aggressive fortification of foods and of a more rapid reduction in the emissions of compounds such as mercury and lead that are neurotoxins. Also, a lot more research into nutritional state and cognitive function should be done. Our brains are our greatest assets and we should err on the side of doing whatever we can to ensure they will develop to reach their fullest genetic potential.

Share |      Randall Parker, 2004 April 20 12:48 AM  Brain Enhancement


Comments
Stefan Jones said at April 20, 2004 10:03 AM:

"In order to improve average level of mental functioning I am an advocate of both more aggressive fortification of foods and of a more rapid reduction in the emissions of compounds such as mercury and lead that are neurotoxins."

Thank goodness we have an administration willing to set aside short-sided industry concerns to address public health issues like this.

Oh, sorry. For a moment there I was in an alternate reality where someone else was president.

* * *

But seriously, yes. Just this morning NPR ran the second in a series about Washington D.C.'s water supply, which delivers a healthy dose of easily ingested *lead* to just those inhabitants who can't afford filtered water and who really, really don't need a biological roadblock to educational progress heaped on top of the social ones.

It isn't cheap to revamp a water distribution system, but what's the cost of entire populations of kids who perform below average?

It would cost to require supplements in, say, milk and bread and cereal, but what is the cost not to?

Randall Parker said at April 20, 2004 10:50 AM:

Stefan, I definitely disagree with the Bush Administration on the regulation of old coal-burning electric power plants. Those plants grandfathered in by 1970s era regulation should be made to meet the same standards as the newer coal-burning plants. I almost said something about that in the body of the main post but I figured it was long enough already and I didn't want to make the post have what might be perceived as a partisan tone. Given that I'm politically on rhe "Right" my views are not motivated by partisanship. But I don't expect all my readers to understand that.

Washington DC lead: Instead of revamping the entire water distribution system it would probably be cheaper to just go into all the houses and apartments and put filters on the kitchen sink faucets. Similarly, a serious effort ought to be made to remove all the old lead paint that remains. One more focused and hence cheaper way to do that would be to test kids in schools and then go into the home of any kid with high blood lead and clean the place.

Stefan Jones said at April 20, 2004 1:18 PM:

I'd be cool with filters. It probably would be WAY cheaper than revamping the water supply.

You would need to figure out a way to keep tenents from selling them, and to be sure they changed filters promptly.

Twice-yearly lead level tests, absolutely. Starting pre-natally.

Randall Parker said at April 20, 2004 1:39 PM:

Yes, prenatal lead testing would be a good idea. I'd make it part of a wider tox panel that would look at mercury and perhaps a few other compounds. I'd also test for some vitamin levels.

Instead of a very expensive comprehensive national health program we could get a much better bang for the buck with highly targetted spending aimed at improving fetal and child development.

Cary said at November 21, 2004 9:28 AM:

Why can't a person absorb iron into the body. What stops the absorption of it through either medication or meats.What is the implication of this in an adult.

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